We stayed here: www.campingophoopvanzegen.nl last April because we wanted to visit the Kukenhof Gardens at Lisse. Small friendly site surrounded by bulbfields, the smell of hyacynths etc was amazing. Like most dutch sites the facilities were fine and everyone was very pleasant. It is a bit north of where you want to be but very close to the coastal motorway.
On the way back we stayed at www.ardoer.com/en/camping/westhove_camping/home/over_de_camping which was very nice if a bit isolated, but the local town of Domburg is very pretty. We had the entire swimming complex to ourselves on a Sunday evening, and all for 13euros/night thanks to the ACSI card.
Hope that this is useful.
Pete
